Serial Port Communication of RFID Reader with Arduino through MAX 233 I.C

Projects General Guidance
1

I have an YR903 Rfid Reader, I want to send data, read by RFID Reader to Arduino Serial Monitor through MAX 233 IC.?

I have to initialize/start Reader by sending Cmd to Reader through Serial Port Comm.,& in return Reader returns a Response Cmd of Successful Connection,but Arduino Serial Monitor is not showing any response from Reader . command to initialize/start RFID READER is : A0 03 FF 79 E5

please help .Its urgent

#include "Arduino.h"
#include <SoftwareSerial.h>

#define DEBUG true
#define rxPin 9
#define txPin 10
SoftwareSerial mySerial (9,10); //rx,tx
byte incomingByte; 

void sendIdentifyCmd ()
{
 
  mySerial.write (0xA0);    
  mySerial.write (0x03);
  mySerial.write (0xFF);  
  mySerial.write (0x79);                  
  mySerial.write (0xE5);                  
 //mySerial.write (0x7d); 

  while(mySerial.available ())
  {
    Serial.println ('cow');
      incomingByte=mySerial.read();
      Serial.print (incomingByte);     
  }
}
void setup ()
{
 pinMode(rxPin, INPUT);
  pinMode(txPin, OUTPUT);
  Serial.begin (115200);
   mySerial.begin (115200);
  Serial.println ("begin initial Serial!\n");
}
//
void loop ()
{
  sendIdentifyCmd ();
 
}

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2

SoftwareSerial does not work at 115200.

3

then at what rate ?
See the attached image

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Capture5.PNG939×191 15.1 KB

4

What that code does is send stuff to the reader, then every time you try and read a byte but their is no byte to read, it sends that load of stuff to the reader again. I am sure you don't want to do that.
From your description I would assume you want to loop until mySerial.available returns a number other than zero, then go in read it and Serial.write to the Arduino's serial monitor.

Also

Serial.println ('cow');

Will send a single character which is returned by the character 'cow', do you want to actually print out cow? If so you need to send "cow".

5

You got things in a right way ,but the problem is still that why Reader is not responsding to Arduino.
mySerial.print(incomingByte) is not printing any thing on Serial Monitor. there can be 2 possibilities ,either the Arduino is not sending commands in a right way or the reader is responding ,but i am not getting response command on Serial Monitor.What you think ?

Serial.println('cow') is not a problem .I don't want to send this cow to anywhere ,It was just a print Statement.I used this statement to check either mySerial.avalable() loop is running or not ? because mySerial.available() will run when there will be some response form Reader.

Thank you

6

What you think ?

I think you should do those changes I suggested, try them and post your code again.
That way we can work towards a solution.

7

Still not working after changes.

#include "Arduino.h"
#include <SoftwareSerial.h>

#define DEBUG true
SoftwareSerial mySerial(6,7); //rx,tx
byte incomingByte; 

void sendIdentifyCmd ()
{
 
  mySerial.write (0xA0);    
  mySerial.write (0x03);
  mySerial.write (0xFF);  
  mySerial.write (0x79);                 
  mySerial.write (0xE5);                  

}
void setup ()
{
  Serial.begin (115200);
  mySerial.begin (9600);
  Serial.println ("begin initial Serial!\n");
  sendIdentifyCmd ();
}
//
void loop ()
{


 if(mySerial.available() > 0)
  {
      Serial.println ("cow");
      incomingByte=mySerial.read();
      Serial.write(incomingByte,HEX);       
  }
 
}
8

OK thanks.
I am still not certain you want to send "cow" before every byte, but I assume nothing is happening. However, the code look OK.
Now are you sure you have your TX and RX defined correctly. Sometimes TX is an output and sometimes it is an input it depends on how the equipment is designated.

You need to test that you are sending stuff out of the Arduino, it is getting through the MAX233 to the reader. Then look at the reader and see if it is sending stuff back.

If you haven't got a scope then you will need something like a LED and resistor. You connect this between the output and 5V or output and 0V depending on if you are looking for a high or low signal. You will be able to see a flash in a normally off signal, where as you will not see a brief off, on a normally on signal.

9

Ok. i will do what u have suggested . Thanks alot .

10

I tried the same. From Arduino to Max3232 ?? No led TxRx to check. from Max3232 to Reader YR903 module ?? I don't know if I can transmit it. Has anyone tested this yet? I look forward to the guidance of everyone.

11

I look forward to the guidance of everyone.

The guidance of everybody would be to please read this:-
How to use this forum

It will tell you not to resurrect or hijack old threads but to start your own.

It will also tell you what information to supply to allow us to help you. It will also tell you to post clickable links to your hardware, just saying "Reader YR903" does not cut it, we need a link to the data sheet or at the very least to the place you bought it from. We need a wiring diagram not a piece of Fritzing physical layout crap and we need the code you are trying to use posted correctly.